Blood oxygenation apparatus



Nov. 25, 1969 p, HQLM ETAL 3,480,401

BLOOD OXYGENATi 0N APPARATUS Filed Aug. 22, 1967 INVENTORS. AALA/V I4 #0444 LOU/S J'PAGG/O United States Patent 3,480,401 BLOOD OXYGENATION APPARATUS Allan P. Holm, Long Beach, and Louis J. Raggio, Covina, Califi, assignors to North American Rockwell Corporation Filed Aug. 22, 1967, Ser. No. 662,368 Int. Cl. A61m 5/00 US. Cl. 23-2585 Claims ABSTRACT OF THE DISCLOSURE An arrangement for oxygenating small volumes of blood by forming the blood into thin film'like streams that flow along an oxygen-premeable membrane through which oxygen is diflusing from a pressurized oxygen chamber.

Background It is well known that the so-called Rh disease endangers a. large number of babies each year. The problem arises when the mother has an Rh negative blood factor, and the child has an Rh positive blood factor. Under these conditions, the childs blood cells invariably leak into the mothers bloodstream, where antibodies are produced. These find their way into the bloodstream of subsequent embryos, andif the infant has an Rh positive blood factorthe antibodies attack the infants red blood cells.

The present solution is to replace the infants blood with entirely new, compatible blood. Because of the infants weakened condition and the fact that the replacement blood may have been stored for an appreciable period of time, it is desirable to oxygenate the replacement blood in order to get the childs system off to a flying start.

In the past, oxygenation equipment has been relatively large, massive, and high-volume; these conditions making it unsuitable for changing the blood of an infantwherein the entire volume required may be only a couple of quarts.

Objects and drawings It is therefore an object of the present invention to provide an improved blood-oxygenation arrangement.

The attainment of this object, and others, will be realized from the following detailed description, taken in Synopsis Broadly speaking, in accordance with the principles of the invention, incoming blood that is to be oxygenated enters a housing, and impinges upon a flow-control unit that forms the bloodstream into thin film-like streams that flow along a membrane that is oxygen-permeable. Pressurized oxygen is applied to a chamber on the other side of the membrane; the oxygen difiusing through the membrane, and infusing into the blood flowing along the membrane.

In this way, the blood is oxygen-enriched; and passes to an outlet from where it is ready to be used in replacing the blood in the infant. The disclosed arrangement is compact; compatible with routine autoclaving techniques; and the entire oxygenating-unit may be sterilized. Where de- 3,480,401 Patented Nov. 25, 1969 "ice sired, the unit may be made transparent to permit surveillance of the infusion operation. The described oxygenating-unit is designed to work by gravity-feed; but the blood may, if desired, be pumped into it, and withdrawn through a pressure-control arrangement, and/or a sampling arrangement that permits continual testingeither chemically or visually--of the oxygen content of the emergent blood.

Description Referring now to FIGURE 1, oxygenation-unit 10- shown in a cross-sectional viewobtains replacement blood from a standard blood bag 11 (FIG. 2). Referring back to FIGURE 1, oxygenation-unit 10 comprises a housing 12, having window-like openings 14 into which are fitted plugs 16a, 16b, 160, etc.; only plugs 16a and being visible in FIGURE 1. Housing 12 has an inlet 18 at its top for admitting blood to be oxygenated; and has an outlet 20 at its bottom for permitting the exiting of the oxygen-enriched blood.

Positioned in the housing, and adjacent to the opening of inlet 18, is a flow-control element 22, that-in the illustrated box-like arrangement-takes the form of a four-sided pyramid. Flow-control pyramid 22 is positioned within the housing in such a manner that its apex is adjacent to an symmetrically aligned with inlet 18, so that the incoming blood impinges onto the apex of flowcontrol element 22, the blood being thus split into four symmetrical streams that flow in thin film-like streams down the surfaces of the pyramid. Flow-control element 22 may be positioned in housing 12 by any suitable means, such as positioning pins 24 and 26.

In order to oxygenate the film-like streams of blood, plugs 16a, 16b, 16c, 16d each has a recess 30a, 30b, 30c, 30d on their inner surface; the recess being connected by a conduit 32a, 32b, 32c, 32d to a source of pressurized oxygen 33. An oxygen-permeable, blood-impermeable membrane 36a, 36b, 36c, 36d is stretched across the inner surface and edges of each plug 16, so that the recess and the membrane form an oxygen chamber 34a, 34b, 34c, 34d.

Plugs 16 are wedge-shaped so that their tapered inner surfaces converge, and are in proximal relation at the lower edges thereof, so that membranes 36 collectively form a passageway to outlet 20.

The plug-membrane assembly (16, 36) is suitably shaped and sized to fit into the window-like openings of the housing; and are either a press-fit or are held in place by suitable detent means, such as springs or latches; so that the lower ends of the flow-control pyramid 22 are adjacent to the upper end of membrances 36. If desired, the plugs may have suitably slanted edges to provide a fit wherein the outer surfaces of the plugs mate With and are positioned bythe outer surfaces of housing 12; the inner surfaces of the membranes being adjacent the inner surfaces of flow-control element 22. The spatial relationship is such that the thin film-like stream of blood flowing along the surfaces of flow-control unit 22 continues to flow, by passing to, and flowing along membranes 36.

When pressurized oxygen is applied to oxygen chambers 34, the oxygen diffuses through the membranes 36, and infuses into the film of blood flowing along the inner surface of membranes 36. Due to the large area and thin film of blood, oxygenation is very diflicult; and an oxygen-enriched stream of blood passes out of outlet 20 at th bot o n f natc adev ce such as a ip-m...

chamber 40 of FIGURE 2frorn whence it is applied to blood-replacing apparatus.

Oxygenation-unit 10 may be formed of stainless steel or a similar material that is readily sterilized, plugs 16 being easily removable to be separately sterilized; or the entire assembled unit may be sterilized. Alternatively, unit 10 may be made of sterilizable transparent material, such as a polycarbonate resin so that the oxygenation process may be visually monitored, since oxygen-enriched blood tends to be redder than oxygen-poor blood.

The above description has been conducted in terms of box-like housing having four sides and a pyramid-shaped flow-control element; but it is apparent that other shapes may be used. For example, if a slower flow of blood is satisfactory, two membranes, rather than four may be used; and under this condition two plugs and a Wedgeshaped flow-control element will suflice.

FIGURE 3 shows another embodiment that has a cylindrical configuration 42 rather than a box-like configuration. This operates in a similar manner; similar elements carrying corresponding reference figures.

Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example only, and is not to be taken by way of limitation; the spirit and scope of this invention being limited only by the terms of the appended claims.

What is claimed is:

1. The combination comprising:

a housing having at least one opening therein;

a plug adapted to fit into said opening, said plug having a recess on the inner surface thereof, and having gas-providing means in communication with said recess;

means-comprising a membrane permeable to said gas,

said membrane extending over said recessfor causing said membrane and said recess to define a gaschamber with the gas in contact with the outer surface of said gas-permeable membrane to permit gas to diffuse from said chamber through said membrane;

said plug and said membrane forming a plug-membrane assembly;

said plug-membrane assembly being inserted in said opening; and

flow-control means, positioned in said housing, for causing blood flowing across said flow-control means, to flow along the inner surface of said membrane, and causing said gas diffusing from said chamber through said membrane to infuse into said blood flowing along said inner surface of said membrane.

2. The combination of claim 1 wherein said housing is substantially box-shaped.

3. The combination of claim 1 wherein said housing is substantially cylinder-shaped.

4. The combination of claim 1 wherein said housing is box-shaped, and has openings in all four walls of said housing;

wherein plug-membrane assemblies are positioned in all said openings; and

wherein said flow-control means comprises a pyramid positioned to split inflowing blood into sheet-like streams that flow along the inner surfaces of respective membranes.

5. The combination of claim 1 wherein said housing has openings in opposite walls of said housing;

wherein plug-membrane assemblies are positioned in said facing openings; and

wherein said flow-control means comprises a Wedge positioned to split inflowing blood into sheet-like streams that flow along the inner surfaces or respective membranes.

6. The combination of claim wherein said plugs are wedge-shaped, and positioned with their inner surfaces converging inwardly to cause the gas-infused blood streams flowing along the inner Surfaces of said membranes to merge at the proximal portions of said plugmembrane assemblies.

7. The combination comprising:

(A) a housing having openings in its side-walls, having an inlet in its top, and having an outlet in its bottom;

(B) a plug-membrane assembly positioned in each said opening, said assembly comprising (a) an opening-shaped-and-sized plug, said plug having (1) an inner surface tapered inwardly and downwardly;

(2) a recess on said inner surface;

(3) a conduit connected to said recess;

(4) an oxygen-permeable membrane stretched across the inner surface and edges of said p (5) said membrane and recess forming an oxygen chamber;

(C) said plug-membrane assemblies being positioned to cause said membranes to form a convergent volume having an exit passageway at its convergent end; and

(D) flow-splitting means, positioned in alignment with said inlet of said housing, for causing blood flowing off said flow-splitting means to flow onto an adjacent membrane.

8. The combination of claim 7 including means for providing pressurized oxygen to said conduits;

means for providing blood to said housing inlet; and

means for collecting blood from said housing outletwhereby oxygen-poor blood introduced into said housing inlet emerges as oxygen-rich blood at said housing-outlet.

9. The combination comprising: 7

(A) a box-like housing having window-like openings in its side-walls, having an inlet in its top, and having an inlet in its top, and having an outlet in its bottom;

(B) a plug-membrane assembly positioned in each said opening, said assembly comprising (a) an opening-shaped-and-sized wedge-like plug,

said plug having (1) a planar outer surface positioned to mate with its side-wall of said housing;

(2) an inner surface tapered inwardly;

(3) a recess on said inner surface of said plug;

(4) a conduit piercing said plug and con necting said recess with said outer surface of said plug;

(5) an oxygen-permeable blood-impermeable membrane stretched across the inner surface and edges of said plug;

(6) said membrane and recess forming an oxygen chamber to be supplied with pressurized oxygen through said conduit;

(C) said plug-membrane assemblies being positioned to cause said membranes to form a convergent volume having an exit passageway at its convergent end adjacent said outlet of said housing; and

(D) pyramid-like flow-splitting means, having the same number of sides as said housing, for causing blood introduced at the apex of said pyramid to flow off the sides of said flow-splitting means to flow onto an adjacent membrane;

(a) said flow-splitting means, having its sides converging to a point positioned adjacent to and in alignment with said inlet of said housing, and having the ends of its diverging sides parallel and adjacent to the upper edges of respective membranes.

10. The combination of claim 9 including means for providing pressurized oxygen to said conduits;

means for providing blood to said housing inlet; and

means for collecting blood from said housing inletwhereby oxygen-poor blood introduced into said 3,341,022 9/1967 Isreeli 210321XR housing-inlet emerges as oxygen-rich blood at said 3,413,095 11/1968 Bramson 23258.5

housing-outlet.

MORRIS O. WOLK, Primary Examiner References (med 5 B. S. RICHMAN, Assistant Examiner UNITED STATES PATENTS U Cl X 3,034,505 5/1962 Sobol 23258.5 3,212,498 10/1965 McKirdy et a1. 23-258.5 210-321 3,332,746 7/1967 Claff et a1. 23-2585 22 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3J+80j+0l Dated November 25, 9 9

I Allan P. Holm/Louis J. Raggio It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Column 2, line 25, "an" should be --a.nd--.

In Column 2, line 6 "difficult" should be --efficient--.

In Column 3, line +0, after "permit" and before "gas" insert --said--.

In Column line 37, remove "and. ha.v".

In Column h, line 38, remove "ing an inlet in its top,"

In Column A, line 75, "inlet" should be --ou'bleb--.

SIGNED AND SEALED JUN 16-1970 (SEAL) Attest:

EdwarflM-Fletnhmlr.

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